JERUSALEM - Israel empowered health officials on Wednesday to quarantine anyone deemed to have been exposed to an especially infectious variant of COVID-19 even if they were previously vaccinated against or recovered from the disease with presumed immunity.

The decision followed a warning by Prime Minister Naftali Bennett on Tuesday over new outbreaks caused by the Delta variant, with daily infections rising after weeks of low plateau credited to Israel's mass-vaccination campaign. 

Under the updated Health Ministry directives, vaccinated or formerly infected people can be ordered to self-isolate for up to 14 days if authorities believe they may have been in "close contact with a carrier of a dangerous virus variant".

Such proximity could include having been passengers on the same plane, the ministry said - a possible dampener on Israel's gradual opening of its borders to vaccinated summer tourists.

Some 55% of Israel's 9.3 million population have received the Pfizer-BioNTech vaccine, and a steep drop in cases prompted most economic restrictions to be lifted. Eligibility for the shots was extended to 12- to 15-year-olds last month but turnout in that age group has been low.

Alarmed by contagions in two Israeli schools last week, Bennett urged parents to vaccinate their adolescents. The Health Ministry said on Wednesday that parents of children who violate quarantine would face fines of 5,000 shekels ($1,540).

($1 = 3.2523 shekels)

(Writing by Dan Williams Editing by Steven Scheer) ((dan.williams@thomsonreuters.com; +972 (0) 2 6322202; Reuters Messaging: dan.williams.reuters.com@reuters.net))